Plasma resonance absorption in interfacial photoemission from very thin silver films on Cu(111)

Very thin silver films deposited on a Cu(111) substrate were studied with the photoemission-into-electrolyte technique. The optical resonance absorption at the silver bulk plasma frequency was observed for films thicker than two monolayers. The correlation between optical absorption and photoemission intensities depends in a complicated fashion on the photon energy as well as the film thickness.